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Finding the Fourth Proportional to 87.70, 120.96 and 77.32

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Solution

The fourth proportional to 87.70, 120.96 and 77.32 is: 106.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.70 : 120.96 = 77.32 : x
  2. Step 2: Convert to fraction form
    87.70/120.96 = 77.32/x
  3. Step 3: Cross multiply
    87.70x = 120.96 × 77.32
  4. Step 4: Simplify right side
    87.70x = 9,352.63
  5. Step 5: Solve for x
    x = 9,352.63/87.70
  6. Step 6: Final answer
    x = 106.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.